Maritime sector use case

Copyright © 2016 Open Geospatial Consortium 13 The objectives for tracking the position of the vessels are twofold: increase the safety and security within the maritime sector. In order to address maritime use cases, the Moving Feature standard has to include at least the following information: i ship position, which can be provided by different data source AIS, LRIT, etc …; and ii ship voyage, which describe the track of a ship. Additional information about the vessel incidents and the ship particulars has to be considered optional and therefore as possible extensions to the Moving Feature standard. For example, the following figure summarize the information collected by the Canonical Data Format produced by the European Maritime Safety Agency Figure 6.8: Canonical Data Format The following map reports the last position of vessels within a specific area black triangle, and the track of a specific vessel yellow triangles. In this case the yellow triangles report the position of a specific vessel every 6 minutes in the last 24 hours. Furthermore additional information as: heading, true heading and speed is recorded to enrich the description of the vessel track. 14 Copyright © 2016 Open Geospatial Consortium Figure 6.9: vessels positions map A vessel has a unique identification at worldwide scale IMO number, or MMSI. The position of a vessel ship position is a point feature over the time. The voyage feature of a vessel ship voyage is characterized by several attributes: speed over the water, course over the water, heading and true heading. In conclusion, to build the trajectory of a vessel two main abstract feature types are relevant for Moving Feature standard: ship position and ship voyage.

6.5 Aviation sector use case

Aircraft and other airborne vehicles are moving features and the aviation sector has a large number of methods to track aircraft and to represent their position. The main sources of tracking data include the following ฀ Primary surveillance radar: Radar equipment measuring position and heading of aircraft. ฀ Secondary surveillance radar: position detection is augmented with an active response from the aircraft’s transponder. It supplies additional information such as its identity. ฀ ADS-B: aircraft with on board GPS or other GNSS equipment may also provide position information based on the GPS measurement. This mode of position and Copyright © 2016 Open Geospatial Consortium 15 information broadcasting is called ADS-B and is seen as an important future tool for increasing air traffic capacity and safety. Figure 6.10: Flight Management and Visualization http:vimeo.com133130574 The position and related data of aircraft is encoded according to different standards. One standard is Eurocontrol ASTERIX http:www.eurocontrol.intasterix . ASTERIX defines different categories. Most categories contain position data according to a different detection method. For instance, category 48 defines the following fields copied from the Cat 48 specification on http:www.eurocontrol.intservicesspecifications-documents Data Item Description Description System Units I048010 Data Source Identifier N.A. I048020 Target Report Descriptor N.A. I048030 WarningError Conditions N.A. I048040 Measured Position in Slant Polar Co-ordinates RHO: 1256 NM, THETA: 360°2 16 I048042 Calculated Position in Cartesian Co-ordinates X, Y: 1128 NM I048050 Mode-2 Code in Octal Representation N.A. I048055 Mode-1 Code in Octal Representation N.A. I048060 Mode-2 Code Confidence Indicator N.A. I048065 Mode 1 Code Confidence Indicator N.A. I048070 Mode-3A Code in Octal Representation N.A.